The development and use of intelligent credit cards or "smart cards" is well known. These devices are made by encasing one or more microelectronic chips in a plastic carrier the size of a credit card. The card generally includes a non-volatile memory for the storage of binary encoded data, and some cards include a CPU chip for limited processing of that data.
Smart cards are considered to be more secure and versatile than the standard embossed plastic credit cards which employ a magnetic stripe for the storage of data . Smart cards may be used for storing a user's financial records, medical history, or other confidential information, and may also be used as security keys to control access to buildings and facilities. Various password schemes and security algorithms have been devised and programmed into the cards to prevent unauthorized use of the cards or access to the data they contain.
In financial transaction applications, for example, the card might carry information related to user's credit balance. A user, desiring to make a purchase, inserts the card into a reader/programmer until in a fixed location, such as a store. The reader/programmer validates the user's personal access code and then deducts the amount of the transaction from the user's credit balance on the card, while charging the amount of the transaction to the user's account in a central bank computer. Examples of data card systems of this type are disclosed in U.S. Pat. Nos. 3,971,916 and 4,007,355, issued to Moreno
Data storage cards such as those discussed above are basically effective, although they suffer from certain disadvantages. Virtually all data cards have an electrical connector which mates with a connector in the reader/programmer unit. The reader/programmer unit supplies the card with power and communicates with the card's internal circuitry through the electrical connector. The electrical connector on the card is subject to wear due to the frictional contact that must be maintained with the connector in the reader/programmer. As the card is used for a period of time, dirt or grit deposits on the connector terminals, making the electrical connections sporadic or ineffective, and rendering the card unusable.
Also, most data cards have a fragile construction, which is inadequate to protect the internal microcircuits during long-term use. Should the data card become exposed to temperature extremes or hostile environments, such as in military use, the data could be damaged or lost. Where a card might contain a patient's vital medical records, such data loss could be catastrophic. Moreover, when the data cards are plugged into or removed from the reader/programmer, electrical sparks can result, which limits their use to environments that are free of flammable or explosive gases.